Spark-plug



W. BOHLEBER.

SPARK PLUG.

APPLICATION FILED JAN. 26, I917.

Patented July 12,1921.

my WQW'YWZWM/ annular shoulder of the core.

UNITED STATES PATENT OFFICE.

WILLIAM BOHLEBER, OF NEW YORK, N. Y.

SPARK-PLUG.

T 0 all whom it may concern.-

Be it known that 1, WILLIAM BOHLEBER, a citizen of the United States, residing at New York, in the county and State of New York, have invented certain new and useful Improvementsin Spark-Plugs, of which the following is a full, clear, and exact description.

The invention which constitutes the subject matter of this application relates to spark plugs and particularly those of the removable core type. It is a matter of common knowledge that the cores of spark plugs manufactured as they are, from porcelain are extremely fragile and any undue strain upon any point invariably causes'it either to crack or chip. The core of a spark plug of the removable type is secured in place by one person under one pressure and by another person under a different pressure. As a matter of fact the amount of pressure put upon the core in securing it in place will vary with the same individual for there is nothing to indicate with any degree of mathematical precision just what pressure is being applied.

I have therefore devised a form of spark plug which equalizes the pressure placed upon the core so that any pressure will be borne uniformly by the entire core which eliminates the setting up of any strains, the construction being such that the pressure placed upon the core to lock the same to the bushing is distributed uniformly upon the seat between the bushing and core. Not only that but; the pressure from the pressure producing means is transmitted in the first instance to the entire circumference of the I find that this enables the core to withstand the maximum amount of pressure and correspondingly decreases the number of breakages.

Other objects and advantages of my invention will appear from the description which follows and from the accompanying drawing, in which,

Figure 1 is a central vertical section illustrating the position of the parts when the core is held in operative or normal position.

Fig. 2 shows the position ofthe parts when the lock nut has been partially unscrewed from the bushing. v

Fig. 3 is a section taken on the line 33 of Fig. 1, the full and dotted lines illustrating the different angles at which the Wrench handle may be inserted into th lock-nu A Specification of Letters Iatent.

Application filed January 26, 1917. Serial No. 144,612.

Figs. At and 5 illustrate a modified form of plug.

Referring first to Figs. 1 to 3 inclusive, the reference numeral 10 designates the bushing, 11 the core or insulator, and 12 and 13 the electrodes of the spark plug, all of which are of known construction except in the particulars hereafter mentioned.

The bushing 10' is provided preferably with concave shoulder let which corresponds with the shoulder 15 on the core 11. The bushinglO is also provided with an exterior screw-thread 16 adapted to receive the screwthreads 17 on the lock-nut 18, while the said loclenut 18 is provided with a plurality of lateral perforations 19 to receive the bifurcations 20 of the handle or wrench 21.

The core is provided with a concave fillet 22 upon which is seated a member 23 whose contacting surface is substantially reversely curved and is of a diameter slightly in ex- ,cess of the diameter of the core at this point of the construction, as will be apparent from the drawings, being such that a ball-bearing effect will be produced at this point so that any inequalities or inaccuracies in either the porcelain, bushing or lock nut will be compensated for by the rolling action of the member 23. In other words the inner face of the member 23, in the specific construction, is more sharply curved than the face of the member 29. with which it contacts. It is obvious that the curmture on the fillet and the metallic member can be reversed to produce the same effect. The member 23 is rigid or non-yielding; that is to say, it has no resiliency,thus effecting a more permanent sealing action between the core and the bushing.

The operation, as regards Figs. 1 to 8 inclusive, is as follows: The bushing 10 is first set in the engine in the usual way as with other types of spark plugs. The core 11 is next inserted within the bushing and then the lock-nut 18 screwthreaded to the bushing 10, as shown in Fig. 3. Or since the interior diameter of the bushing 18 is slightly greater than the greatest diameter of core, it would be equally feasible to screwthread the lock-nut to the bushing before the core is placed thereon. However this is a matter of taste. The bifurcations 20 of the handle 21 are then projected laterally through the perforations 19, as shown, for instance, 1n the full linesof Fig. 3, it being of course understood that in the particular construcagainst the upper walls oi? the lateral p tion shown the handle wouldbe inserted from three other directions, as shown in dotted lines. The position of the parts at this point is that clearly shown in Fig. 2. If the handle is now given a turning movement in the proper direction, depending of course, ugon whether a right or left hand screwthread is used, the loclenut 18 will be moved toward the core and cause the bifurcations to engage the member 23, as shown in Pg. 1. Any further movement after engagement will result in a forcing or tightening action between. the shoulders of the core and bushing. So long as the core is loose and in the position shown in Fig. 2 the handle 21. is free to be withdrawn laterally from the perforations 19, but when in normal operative positions, as shown in Fig. 1, it cannot fall out as it is held therein by the upward pres sure oi the core and the dew ward pressure of the bushing. In the construction shown the handle 21 may be placed in any one of four positions (see Fig. and should-there be any obstructions preventing its complete rotation the handle may be moved as iar as it will go, withdrawn from the lateral perforations, and moved baclnvardly to a succeeding position. In this way the handle may be given at least a quar er turn at each operation, and this operation repeated until the bifurcations 20 oi": the handle 21 engage with the top of the metallic member placed thereon. lifter this engagement only a slight move ent of the handle required to eliect a fluid tight connection bet veen the shoulders i l and 15. The upward pressure on the bifurcations by their engmgymnent with the core causes said biturcations to bind rations and the upper surface of the met-ville washer 22, and the tighter the loclenut is screwed down the tighter this binding engagement becomes. To remove the core it is only necessary to reverse the handle slight? say from one-tl1irty-second to one eighth oi a turn, when the biiuling engagement referred to is broken and the handle may be withdrawn laterally trom the perforations 1!), leaving the core tree to be withdrawn from the bushing.

' In Figs. i and 5 is illustrated a modified form of plug in which the bushing 24; is provided with bayonet slots 25 to receive the cocen "ric bale 26 secured to the sleeve 27 which is either fixed to or loosely mounted upon the core 28, By fixed I mean that it is not removable from the core. In any event the upper portion of the sleeve member is of a greater diameter than the diameter 01" the core considering the diameter of the core taken in the plane of the upper edge of the sleeve when the latter is in normal position. It will be understood that the pressure in this form of plug is applied by means of the rotating eccentric bale 26.

From the above it will be seen that l have devised a spark plug in which the strain due to inaccuracies oi the parts is entirely eliminated, as the member 23 bears equally upon all portions oi: the fillet or shoulder 22. It is to be understood, however, that I do not limit myself to the construction shown, but only by the limitations imposed by the appended claims.

lVhat I claim as my invention is:

l. A spark plug comprising a bushing, a removable core for the bushing, a hollow rotatable lock-nut screw-threzuled to the bushing, in combination with a. member adapted to rotate the same, said member having a bifurcated portion for straddling the upper portion of the core and adapted to apply pressure to the latter, and means for equalizing the pressure upon said core.

2. In a. spark plug of the removable core type, a bushing, a core and means for securing the core to the bijishing, comprising a sleeve member surrounding said core and adapted to engage the surface of the samein a plurality of planes and means for applying pressure to said sleeve member.

8. In a spark plug of the removable core type, a bushing, a core, and means for securing the core to the bushing, comprising a rockable sleeve member loosely surrounding said core and adapted to adjustably seat thereon, and means removable laterally from said plug and engaging said sleeve member to transmit pressure to the core.

41:. In a spark plug of the removable core type, a bushing, a core, and removable means for securing the bushing to the core, comprising a non-yiel ding device adjustably engaging the core to compensate for any inaccuracies in the manufacture of the parts,

53. .l a sparl: plug otthe removable core type, a bushing, a core, and removable means tor securing the bushing to the core, comprising a pressure producing means and a sleeve member having a ball-and-socket seat upon the core and adapted to transmit the pressure from said pressure means to the core.

6. In a spark plug, the combination of a relatively fixed member, an electrode carrying insulator adapted to removably seat therein, an element provided with an operating handle by which said element may be removed by movement in a plane transverse to the axis of the insulator and by which said element may be actuated so as to apply pressure to the insulator in the direction of its axis to lock the insulator to its seat, and means interposed between said element and said core and adjustably' seated upon the latter to compensate for any irregularities in the parts.

7. In a spark plug, the combination of a relatively fixed member, an electrode carrying insulator adapted to removably Seat therein, an element removable by movement in a plane transverse to the axis of the insulator and adapted to be so actuated as to apply pressure to the insulator in the direction of its axis to lock the insulator to its seat, and means interposed between said element and said core and adjustably seated upon the latter to compensate for any irregularities in the parts.

8. In a spark plug, the combination ofa relatively Iixed member, an electrode carrying insulator adapted to removably seat therein, a single element comprising a plurality of separated portions connected by operating means and rotatable about an axis transverse to the axis of the insulator to apply pressure to lock it to its seat, and means interposed between saidelement and the insulator for uniformly transmitting the pres sure from the pressure element to said core.

9. In a spark plug, the combination of a relatively fixed member, an electrode carrying insulator adapted to removably seat therein, a single element comprising a plu rality of separated portions connected by operating means and rotatable about the axis of the insulator to apply pressure to lock it to its seat, and means interposed between said element and said core and adjustably seated upon the latter to compensate for any irregularities in the parts.

10. In a spark plug, a bushing and a removable core provided with a shoulder adapted to seatin said bushing, in combination with a removable pressure means for forcing said core to the seat in said bushing, and means for distributing the pressure uni- ,formly around said shoulder comprising a solid member to receive the pressure from said pressure means and adjustably engagin said core.. 7

11. In a spark plug, a bushing and a removable core provided with a shoulder the lower side of which is adapted to seat upon a shoulder in said bushing and the upper side of which is provided with a curved sur.

face, in combination with a removable pressure means for forcing sa1d core to its seat in said bushing, and means for distributing the pressure uniformly around said shoulder comprising a solid member interposed between said pressure means and the core the lower surface of which is curved to corre ber interposed between said pressure applying member and the shoulder of the core, the curvatures of the inner face of sa1d second mentioned member and the said shoulder being such as to enable a movement of the axis of one relative to the axis of the other.

13. In a spark plug, abushing, and a removable core therefor having a curved bearing shoulder, in combination with means for securing said core to the bushing comprising a pressure applying member and a member having an inner curved face interposed between said pressure applying member and the shoulder of the core, the face of one of said members being curved more sharply than the other whereby the pressure exerted by said pressure applying member is distributed uniformly upon the core.

14:. In a spark plug, a bushing, and a removable core therefor having a curved bearing shoulder, in combination with means for securing said core to the bushing comprising a pressure applying member and a member interposed between said pressure applying member and the shoulder of the core, the inner face of the second mentioned member being curved more sharply than the shoulder of said core whereby the pressure exerted by said pressure applying member is distributed uniformly upon the core.

In testimony whereof I ailix my signature.

WILLIAM BOHLEBER. 

